12111551 has 4 divisors (see below), whose sum is σ = 12154632. Its totient is φ = 12068472.

The previous prime is 12111527. The next prime is 12111563. The reversal of 12111551 is 15511121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12111551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21116 + ... + 21681.

It is an arithmetic number, because the mean of its divisors is an integer number (3038658).

Almost surely, 2^12111551 is an apocalyptic number.

12111551 is a deficient number, since it is larger than the sum of its proper divisors (43081).

12111551 is an equidigital number, since it uses as much as digits as its factorization.

12111551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43080.

The product of its digits is 50, while the sum is 17.

The square root of 12111551 is about 3480.1653696340. The cubic root of 12111551 is about 229.6500727978.

Adding to 12111551 its reverse (15511121), we get a palindrome (27622672).

The spelling of 12111551 in words is "twelve million, one hundred eleven thousand, five hundred fifty-one".